The present invention generally relates to apparatuses such as a television signal processing apparatus that comprise multiple tuners and receive auxiliary data such as administrative data, program guide information or emergency alert signals.
Modem signal processing apparatus typically include signal processing circuitry for processing a multitude of signal formats, such as NTSC, ATSC, QAM, or satellite signals. Such a signal processing apparatus typically includes various components such as a tuner for selecting a particular signal or channel from a plurality of signals or channels received by the apparatus. To process digital signals, such as ATSC or satellite signals, the signal processing circuitry, and in particular the tuner, must perform these functions with high-speed digital circuitry. A potential undesirable result of high-speed signal processing is that temperature rise of components used in the signal processing apparatus may approach or exceed reliability limits. It is desirable to reduce the overall operating temperature of the signal processing apparatus when possible to increase the reliability of the signal processing apparatus and to reduce power consumption of the signal processing apparatus during operation.
Signal processing apparatus have various modes of operation depending on its state of use. For example, a signal processing apparatus is in an off mode when it is completely disconnected from a power source. The signal processing apparatus may have a standby mode of operation wherein it is connected to a power source and capable of tuning and receiving particular signals or channels, storing auxiliary data transmitted via these signals or channels, and receiving and processing remote control commands, such as an “on” command, but not operational for producing audio or video output signals. Furthermore, during an on mode of operation the system is fully operational and normally all components are powered and fans can be used to cool the signal processing apparatus. During certain modes of operation certain system components may be disabled to reduce power consumption and noise. In particular, components such as a cooling fan intended to minimize excessive temperature rise of components may be disabled. As a result, component heating may be exacerbated during a mode of operation such as “standby” mode. However, it is not possible to remove power to all components during standby mode as the signal processing apparatus is still required to tune and receiving particular signals or channels, store auxiliary data transmitted via these signals or channels, and receive and process remote control commands. In particular it is desirable to reduce the heat generated by high speed signal processing circuitry associated with the tuners while continuing to receive auxiliary data such as administrative data, guide data, or emergency alert notifications.